diff options
| -rw-r--r-- | fs/userfaultfd.c | 28 | ||||
| -rw-r--r-- | include/linux/userfaultfd_k.h | 5 | ||||
| -rw-r--r-- | kernel/fork.c | 5 |
3 files changed, 37 insertions, 1 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 68cdd89c97a3..7c0bd0b55f88 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -692,6 +692,34 @@ void dup_userfaultfd_complete(struct list_head *fcs) } } +void dup_userfaultfd_fail(struct list_head *fcs) +{ + struct userfaultfd_fork_ctx *fctx, *n; + + /* + * An error has occurred on fork, we will tear memory down, but have + * allocated memory for fctx's and raised reference counts for both the + * original and child contexts (and on the mm for each as a result). + * + * These would ordinarily be taken care of by a user handling the event, + * but we are no longer doing so, so manually clean up here. + * + * mm tear down will take care of cleaning up VMA contexts. + */ + list_for_each_entry_safe(fctx, n, fcs, list) { + struct userfaultfd_ctx *octx = fctx->orig; + struct userfaultfd_ctx *ctx = fctx->new; + + atomic_dec(&octx->mmap_changing); + VM_BUG_ON(atomic_read(&octx->mmap_changing) < 0); + userfaultfd_ctx_put(octx); + userfaultfd_ctx_put(ctx); + + list_del(&fctx->list); + kfree(fctx); + } +} + void mremap_userfaultfd_prep(struct vm_area_struct *vma, struct vm_userfaultfd_ctx *vm_ctx) { diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index 9fc6ce15c499..cb40f1a1d081 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -249,6 +249,7 @@ static inline bool vma_can_userfault(struct vm_area_struct *vma, extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); extern void dup_userfaultfd_complete(struct list_head *); +void dup_userfaultfd_fail(struct list_head *); extern void mremap_userfaultfd_prep(struct vm_area_struct *, struct vm_userfaultfd_ctx *); @@ -351,6 +352,10 @@ static inline void dup_userfaultfd_complete(struct list_head *l) { } +static inline void dup_userfaultfd_fail(struct list_head *l) +{ +} + static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, struct vm_userfaultfd_ctx *ctx) { diff --git a/kernel/fork.c b/kernel/fork.c index 89ceb4a68af2..597b477dd491 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -775,7 +775,10 @@ out: mmap_write_unlock(mm); flush_tlb_mm(oldmm); mmap_write_unlock(oldmm); - dup_userfaultfd_complete(&uf); + if (!retval) + dup_userfaultfd_complete(&uf); + else + dup_userfaultfd_fail(&uf); fail_uprobe_end: uprobe_end_dup_mmap(); return retval; |